If its raining, its probably not that cold - as in not below freezing. If it were below freeezing, I would probably wear a lightweight snowbaording pant.

I wear a pair of Zoic pants that I got at REI for like $60. They are a lightweight softshell type material, not too warm, but I dont get cold in them either. I am comfortable in the 30s with them. The fit and appearance is almost between a pair of Dickeys and a pair of Dockers casual khakis. So, for me, they work well. I imagine that if you are considering pants that look nice but are still bikeable, they would probably be just fine for you too.

They are water resistant, but not waterproof. So, light drizzle, they are fine. Anything more than that, and you are getting wet. I sometimes wear a pair of Goretex pants over them before with good luck.